U.S. patent application number 13/720043 was filed with the patent office on 2014-06-19 for adaptive velocity tracker.
The applicant listed for this patent is Rudi Bertocchi. Invention is credited to Rudi Bertocchi.
Application Number | 20140166843 13/720043 |
Document ID | / |
Family ID | 50929823 |
Filed Date | 2014-06-19 |
United States Patent
Application |
20140166843 |
Kind Code |
A1 |
Bertocchi; Rudi |
June 19, 2014 |
ADAPTIVE VELOCITY TRACKER
Abstract
The disclosure is directed to a high precision two axis tracking
system having adaptive angular velocity comprising: a pedestal
coupled to a foundation; a slew drive comprising a modular velocity
rotation driver operably coupled to the pedestal; an azimuth yoke
operably coupled to the slew drive and hingedly coupled to an
elevation hub; an elevation hub comprising a modular velocity
elevation driver, hingedly coupled to the azimuth yoke; a
directional apparatus configured to be precisely pointed towards a
target, operably coupled to the elevation hub; and a processor
operably coupled to the tracking system.
Inventors: |
Bertocchi; Rudi; (Herzliya,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bertocchi; Rudi |
Herzliya |
|
IL |
|
|
Family ID: |
50929823 |
Appl. No.: |
13/720043 |
Filed: |
December 19, 2012 |
Current U.S.
Class: |
248/550 |
Current CPC
Class: |
H01Q 3/08 20130101 |
Class at
Publication: |
248/550 |
International
Class: |
F16M 11/18 20060101
F16M011/18 |
Claims
1. A high precision two axis tracking system having adaptive
angular velocities comprising: a pedestal like unit coupled to a
foundation; an elevation hub comprising a horizontal rotational
degree of freedom; an azimuth yoke operably coupled to the
elevation hub; a slew drive unit for azimuth positioning,
comprising an inner ring and an outer ring, one ring rigidly
coupled to the pedestal and one ring coupled to the azimuth yoke; a
linear screw drive unit for elevation positioning, simultaneously
coupled to the elevation hub and the azimuth yoke; directional
apparatus to be precisely pointed towards a target; encoders
operably coupled to rotational shafts; and a processing unit for
controlling and networking the tracking system with associated
auxiliary systems.
2. The system of claim 1, wherein said directional apparatus may be
an antenna of arbitrary form, a dish-like energy concentrator, an
energy concentrator of arbitrary form, a pointing device, an
illumination device, a listening device, a microphone device, an
imaging device, a data collecting or transmitting device or any
apparatus that require for its operation the continuous precise
positioning in azimuth and elevation.
3. The system of claim 1, wherein said elevation hub comprises: a
flat mounting surface interfacing with the directional apparatus; a
generally cylindrical housing rigidly affixed to said flat mounting
surface; a flat protruding control horn simultaneously rigidly
affixed to said cylindrical housing whilst operably coupled to a
linear screw drive; and a horizontal shaft protruding from said
housing whilst supported by at least one bearing.
4. The system of claim 3, wherein said control horn is tapered,
elongated and located above the horizontal rotational shaft for the
purpose of increasing the linear screw drive's elevation moment
whilst ensuring that said linear screw is solely loaded in tension,
thus eliminating over-dimensioning of said linear screw due to
Euler slender budding.
5. The system of claim 1, wherein the azimuth yoke comprises
generally flat metal plates incorporating interface provisions for
the slew drive, the linear screw drive, the elevation hub, a
plurality of control boxes and routing devices.
6. The system of claim 5, wherein the azimuth yoke extends
rearwards acting as a ballast to the directional apparatus, thus
generally alleviating the elevation moment vis a vis the horizontal
shaft.
7. The system of claim 1, wherein said pedestal unit may be
fabricated from metal or concrete or a combination thereof and
further rigidized by means of external or internal bracing
comprising a combination of wires, ropes, tubes, bars or
struts.
8. The system of claim 1, wherein the slew drive is powered by a
controllable and/or reversible electrical motor, a pneumatic
device, a hydraulic device, or a device comprising at least one of
the foregoing.
9. The system of claim 8, wherein the motorized slew drive unit is
fitted with a train of serially connected modular gear units, said
modular gear units being quickly interchangeable and/or
exchangeable for the purpose of modifying said slew drive unit's
angular velocity by means of adapting the total input gear ratio as
a response to varying requirements in the azimuthal angular
velocity.
10. The system of claim 8, wherein the motorized slew gear unit is
fitted with either a variable friction device, torque limiting
device or a clutch device or a combination thereof capable of
disconnecting the slew gear unit from the modular gear unit train
at a predefined torque, thus enabling the slew gear to float into a
trimmed azimuthal position having only a minimal torque.
11. The system of claim 1, wherein the linear screw drive unit is
powered by means of at least one controllable/reversible electrical
motor, one pneumatic device or one hydraulic device or a
combination thereof.
12. The system of claim 1, wherein the linear screw drive is
operably coupled to the elevation hub by means of a rod end clevis
and to the azimuth yoke by means of a bearing supported trunnion
mount.
13. The system of claim 11, wherein the motorized linear screw gear
unit is fitted with a train of serially connected modular gear
units, said modular gear units being quickly interchangeable and/or
exchangeable for the purpose of modifying the screw drive unit's
linear velocity by means of changing the total input gear ratio as
a response to varying requirements in the elevational angular
velocity.
14. The system of claim 1, wherein said processing unit is inputted
data from a plurality of onboard and external sensors for the
purpose of processing the inputted data by stored algorithms, said
algorithms may be adapted to the specific operation of different
directional apparatus.
15. The system of claim 14, where a closed loop control algorithm
is inputted a measured spatial error of the target tracking, said
algorithm may use proportional, integral and differential analysis,
or any combination thereof, of new and stored spatial error
measurements to issue optimized control command to the azimuth and
elevation drive motors for the purpose of rapidly minimizing the
tracking error.
16. The system of claim 14, where a control algorithm is
specifically inputted ambient atmospheric data, said algorithm
outputting protective stow commands to the tracking unit should the
operational conditions of the system be exceeded.
17. The system of claim 14, wherein said processing unit combined
with stored control algorithms issue commands and information to a
plurality of auxiliary systems comprising: pumps, fans, chillers,
deicing devices, heating elements, lights, cameras, warning
systems, computer data storage and processing devices etc.
18. The system of claim 1, wherein said tracking device operates
either as a single unit or as part of a plurality of trackers
grouped in a cluster, said cluster of trackers generally supervised
and controlled by a local processing unit having either cabled,
wireless or internet network connection or a combination thereof to
each tracker.
19. The system of claim 18, wherein clusters of trackers may be
globally dispersed and each cluster's local processing unit is
networked with a central processing unit, said network connection
being either cable, wireless or internet or a combination
thereof.
20. The system of claim 19, wherein said central processing unit is
controlled by either a local or remote command station, said
command station may be manned or autonomous and communicating with
the central processing unit either by cable, wireless or internet
or a combination thereof.
Description
BACKGROUND
[0001] The disclosure generally relates generally to spatial
tracking systems and more particularly to numerically controlled
two axis tracking systems
[0002] Present precision tracking devices with pointing accuracies
better than 1 milliradian (mrad) may be generally divided into
three families: (i) tracking devices for flight vehicles and/or
missiles or other relatively fast moving targets (ii) tracking
devices for earth orbiting satellites (low or high) or other quasi
static targets and (iii) tracking devices for astronomical bodies
or other virtually static targets. The principal difference between
the types of tracking families lies in the angular velocity and
angular acceleration of the tracked target. So called "solar
trackers" for simple flat panel photovoltaic applications or other
crude systems are deemed irrelevant to the following discussion due
to their low accuracy.
[0003] Representative applications for the first family of tracking
devices are radar and anti-aircraft defense systems. Said systems
require high angular velocities to track fast-moving, relatively
close targets, especially at low altitudes, which requires trading
pointing accuracy for high angular rotational velocities and
accelerations of the azimuth and elevation axes. Typical angular
velocities and accuracies of such a tracking system may be
represented by the ORBIT AL-4048 tracker, which may reach angular
velocities of 15 deg/sec with pointing accuracy of .+-.1 mrad.
[0004] An example of the second family, e.g., earth orbiting
satellite trackers, is the General Dynamics VA 18.3 meter antenna
system. It has a turning head pedestal in an elevation over azimuth
axis configuration. For this specific system the azimuthal rotation
range is limited to 270 degrees, while the elevation range is 0-90
degrees. The pointing accuracy of said system is .+-.0.4 mrad. The
angular velocities stated by the manufacturer are 1.5 deg/sec in
azimuth and 10 deg/sec in elevation. The tracking system is mounted
on a concrete tower. The described system is, therefore, very
heavy, the antenna weighing 27 metric tons and the pedestal 32
metric tons. Furthermore, the electrical power required to operate
the system is 120 kVA.
[0005] Space telescopes and deep space antennae represent the third
family of tracking devices; the tracked target is distant,
virtually static and has a very small viewing angle--demanding a
very high pointing accuracy, 0.01-0.1 mrad. Such high pointing
accuracy may be typically achieved by trading angular velocity for
pointing accuracy. The ten meter antenna design of the National
Radio Astronomy Observatory (NRAO) may be considered to represent
one aspect of the current state of art in the design of tracking
devices for high accuracy pointing. The claimed pointing accuracy
of said antenna is about 5 .mu.rad at a claimed maximum angular
velocity of 6 deg/sec. The two axis tracking is performed by an
elevation over azimuth system, with a yoke for enabling elevation
and a plane bearing for azimuth motion. The yoke is manufactured
from welded steel plates, causing large internal stresses due to
the welding process which cannot be relieved by temperature baking
and/or annealing due to the risk of structural deformations.
[0006] Likewise, the azimuth bearing of this antenna has a diameter
of 2.4 m and deforms unless it is uniformly loaded. Furthermore,
unless the bearing mounting faces are sufficiently stiff the weight
of the structure will cause the bearing to be distorted regardless
of how flat the mounting surfaces had been machined.
[0007] In the aforementioned tracking systems both the elevation
and azimuth axes are driven by similar friction drives acting on a
drive ring of each respective axis. This methodology of controlling
the azimuth and elevation angle is plagued by several problems; (i)
a single friction drive may not be sufficient to overcome the
inherent friction of the system; (ii) that same friction drive may
"burn out" if the drive friction momentarily peaks due to abrupt
external loads such as wind gusts (especially with the large
diameter antennae) or unbalanced mass distribution; (iii) the
stiffness of the drive may be insufficient unless (expensive)
carbide roller shafts are used; (iv) there is a risk of "welding"
between the drive roller and the drive wheel; and (v) excessive
thrust loading might be generated unless the roller axis is very
carefully aligned, reducing the fault tolerance of the whole
system. To sum, the proposed tracking device of the aforementioned
system is very large and heavy, has large internal weld stresses
which cannot be relieved without risking structural deformations
and its drive system is likely to fail or degrade when subjected to
unbalanced loads
[0008] An alternative methodology for pointing a large antenna may
be the Jet Propulsion Lab's "Deep Space Station 15: Uranus" 34
meter antenna. It is equipped with an electrically driven
azimuth-elevation type of tracking device. The antenna rotates in
azimuth on four self-aligning wheel assemblies that ride on a
precisely leveled circular steel track. The track is held in place
by 16 tangential links that attach to a centrally reinforced
concrete pedestal. The antenna steel structure is attached to an
elevation bull gear wheel which drives it up and down. The
operating speed of this antenna is 0.4 deg/s for both azimuth and
elevation. It is obvious from the above that whilst being an
acceptable solution for very large and heavy (in the order of
hundreds of metric tons) antennae, it is far too complicated and
expensive for commercial antennae.
[0009] Accordingly, a need arises for a tracking system where
regardless of the distance to the target, pointing accuracy is not
compromised, thereby being capable of tracking targets ranging from
fast moving airplanes to virtually static astronomical entities at
a significantly reduced cost and complexity whilst maintaining the
required level of pointing precision.
SUMMARY
[0010] Disclosed, in various embodiments, are spatial tracking
systems. Specifically, the disclosure relates to numerically
controlled two axes tracking systems.
[0011] In an embodiment, provided herein is a high precision
tracking system having adaptive two axis angular velocity
comprising: a pedestal coupled to a foundation; a slew drive
comprising a modular velocity rotation driver operably coupled to
the pedestal; an azimuth yoke having a fore side and an aft side
operably coupled to the slew drive at the fore side and hingedly
coupled to an elevation hub comprising a modular velocity elevation
driver, operably coupled to the azimuth yoke; a directional
apparatus configured to be precisely pointed towards a target,
operably coupled to the elevation hub; and a processor operably
coupled to the tracking system.
[0012] In another embodiment, provided herein is a cluster,
comprising: a plurality of the tracking systems described herein,
the tracking systems being in electronic communication with a
cluster central processing unit (CCPU).
[0013] In another embodiment, provided herein is a spatial tracking
systems capable of quickly adapting the system's angular velocity
and pointing accuracy to the tracked target's specifics by changing
modular gear units in the gear train of the motorized azimuth and
elevation drives.
[0014] In one embodiment, the tracking system may comprise a
radiation concentrator as described in U.S. Pat. No. 7,156,531
disclosing a parabolic concentrator, incorporated herein by
reference in its entirety to the disclosure of this application for
all purposes.
[0015] These and other features of the spatial tracking systems
will become apparent from the following detailed description when
read in conjunction with the drawings, which are exemplary, not
limiting, and wherein like elements are numbered alike in several
figures.
BRIEF DESCRIPTION OF THE FIGURES
[0016] For a better understanding of the spatial tracking systems,
with regard to the embodiments thereof, reference is made to the
accompanying drawings, in which like numerals designate
corresponding elements or sections throughout and in which:
[0017] FIG. 1 shows a general isometric view of an embodiment of
the spatial tracking systems;
[0018] FIG. 2 shows an exploded assembly view of the principal
components of an embodiment of the spatial tracking systems;
[0019] FIG. 3 shows an isometric view of the elevation hub of an
embodiment of the spatial tracking systems;
[0020] FIG. 4, is an exploded assembly view of the azimuth yoke of
an embodiment of the spatial tracking systems;
[0021] FIG. 5, shows an exploded assembly view of the slew drive's
gear train;
[0022] FIG. 6, shows an exploded assembly view of the elevation
drive's gear train;
[0023] FIG. 7, shows a schematic depicting the general input/output
stream of the tracker's on-board processor; and
[0024] FIG. 8, shows a network operational scheme depicting the
supervision, operation and control of several clusters of trackers,
either local or remote.
DESCRIPTION
[0025] The present disclosure thus provides in a first aspect, a
high accuracy, two axis tracking system that is insensitive to the
distance of the tracked object, comprising: a rigid pedestal which
can serve as an attachment base for the tracking system, with
sufficient height to provide interference-free movement of the
installed directional apparatus; a motorized slew drive for
generating the desired azimuthal motion. The slew drive is
configured to have a modular and quick exchangeable gear train for
rapidly obtaining the desired combination of azimuthal angular
velocity and pointing accuracy, which can enable continuous
tracking of a target with only minimal angular accelerations and no
direction reversals. The tracking system can further comprise a
clutch or torque limiting system capable of disconnecting the slew
drive at excessive torques, enabling the tracking system to realign
itself to the wind into a trimmed condition. An azimuth yoke can be
incorporated, consisting of assembled steel plates operably coupled
to the slew drive, where the plates can have provisions for the
elevation shaft, with a screw gear drive and auxiliary systems; a
central hub comprising a bored face plate (or mounting bracket) for
mounting the directional apparatus, a horizontal elevation
rotational shaft and an elongated control horn simultaneously
serving as an elevation moment multiplier and a coupling point for
the elevation drive. The system can further comprise two high
precision angular motion encoders, operably coupled to the drive or
rotational shafts of either the azimuth or elevation drives, for
precisely and accurately measuring the azimuth and elevation
angles. In an embodiment, the term "encoder" is a general term
including any device suitable for performing continuous angular or
linear measurements and transmission of the resulting signals to a
receiving and processing unit. The term "encoder" refers to
displacement transducers in which the interaction between the
stationary and moving elements is based on a repetitive pattern,
with a either binary or continuous output signal. The encoders can
be, for example, optical or capacitive, full-rotation, absolute
angle encoders, which can convert rotation angle into an output
signal based on interaction between a fixed and a moving part.
These encoders can be built to provide an output signal that
repeats once or more times per rotation.
[0026] The elevation hub used in the tracking systems described
herein can have a geared screw drive for generating the desired
elevation motion of the directional apparatus. The screw-drive can
be configured to have a modular and quick exchangeable gear train
for rapidly obtaining the desired combination of elevation angular
velocity and pointing accuracy, which can enable continuous
tracking of the intended target with only minimal angular
accelerations and minimal direction reversals. The screw-drive can
be operably coupled to the elevation hub's control horn above the
elevation rotation axis, thus ensuring that the elevation drive
screw is always loaded in tension--eliminating expensive over
dimensioning of the elevation drive due to Euler buckling of the
screw, or threaded shaft.
[0027] The processor used in the spatial tracking systems described
herein can comprise: a user interface; a transceiver; and a
non-volatile memory, wherein the processor is configured to receive
data from a plurality of onboard and external sensors and/or
systems. A closed loop, low order control system can be
incorporated into the processor, which can measure the pointing
error and execute correcting commands to the tracking system for
minimizing the tracking error. The control system can also activate
auxiliary subsystems such as pumps, fans, lights, heating coils or
other similar system comprising at least one of the foregoing or
their combination in accordance with predefined control algorithms
and environmental sensor scripts stored in the processors memory.
Scripts and other algorithms can be uploaded into the processor
remotely, using any suitable communication means, for example,
wired, wireless, internet, radio and other electronic communication
means. The control system used in the spatial tracking systems
described herein can also use a variety of on-board, environmental,
remote or satellite-based sensors to determine if the environmental
operational limits are exceeded thereby driving the tracking system
into a predefined protective stow position. The control system used
in the spatial tracking systems described herein can also comprise
a high-order control system, which can enable a single tracking
system to operate as a part of a network of tracker clusters;
either local or remote. The high order control system can be
configured to further report the operating status of each networked
tracking system to either a local or a remote manned or autonomous
supervising station by means of a cabled, internet, wireless
connection or electronic connection.
[0028] In an embodiment, the term "electronic communication"
indicates that one or more components of the tracking systems
described herein are in wired or wireless communication or internet
communication so that electronic signals and information can be
exchanged between the components in a bidirectional manner.
[0029] The slew drive used in the spatial tracking systems
described herein can comprise an inner ring coupled to the pedestal
and an outer housed ring coupled to the azimuth yoke. The height of
the pedestal can be configured to provide the directional
apparatus, with uninterrupted pitch from about 6.degree. below the
horizon, to 90.degree. above the horizon. Likewise, the slew-drive
can continuously rotate the directional apparatus 360.degree..
Likewise, the pedestal may be fabricated from metal or concrete or
a combination thereof and further stiffened by means of external or
internal bracing comprising a combination of wires, ropes, tubes,
bars or struts. The directional apparatus can be, for example, an
antenna of arbitrary form, a dish-like energy concentrator, an
energy concentrator of arbitrary form, a pointing device, an
illumination device, a listening device, a microphone device, an
imaging device, a data collecting or transmitting device or a
pointing device comprising at least one of the foregoing.
[0030] The elevation hub used in the spatial tracking systems
described herein may further comprise a mounting bracket having a
front coupled to the directional apparatus and a back side coupled
to a cylindrical housing. The housing can have any appropriate
cross section and does not necessarily have a cylindrical cross
section. In an embodiment, the housing can also have a square or
hexagonal cross section. The housing coupled to the mounting
bracket can also be hingedly coupled to the azimuth yoke. The
mounting bracket may further have a control horn disposed thereon,
that can be configured to hingedly couple to a threaded shaft used
in the screw-gear of the elevation hub.
[0031] The term "hingedly" refers in an embodiment, to a coupling
of one or more components which allow the second component to pivot
with respect to the first component. "Hingedly" can also refer to a
method of mounting one component to another such that the two
components can hinge or move relative to one another, and is not
intended to be limited to a connection comprising an actual hinge.
"Hingedly coupled" indicates that the orientation of one component
relative to the other can be varied. This may be because of a form
of mechanical connection that permits relative movement, for
example a pivot, a rod end, or a hinge pin. There may be an
intermediate portion which is hinged at respective spaced locations
to the first and second portions, allowing a greater degree of
hinging in one or more directions. A hinging device may be
lockable. Hinged portions may be separable.
[0032] The elevation hub used in the spatial tracking systems
described herein can further comprise: a trunnion mount, hingedly
coupled to the aft side of azimuth yoke; a linear screw drive
having a proximal end operably coupled to the control horn via a
rod end clevis, and a distal end coupled to the trunnion mount via
a bearing. Moreover, the linear screw drive can be driven by a
controllable and reversible electrical motor, a pneumatic device, a
hydraulic device or any driving mechanism comprising at least one
of the foregoing. In addition, the linear screw gear is operably
coupled a train of serially coupled and interchangeable modular
gear units configured to modify the linear screw drive's unit
angular velocity by changing the total gear ratio as a response to
varying requirements in the angular elevational velocity. As used
herein, the term "interchangeable" indicates that the gear unites
used in the spatial tracking systems described herein can be used
in any order that will provide the required angular elevation
velocity. For example, the gear units can be used to increase
angular elevation mobility by sequentially increasing the ratio
between the driving mechanism and the screw drive, thus able to
track high velocity and/or short range, without compromising
pointing accuracy. In an embodiment, the spatial tracking systems
described herein have a pointing accuracy of angular elevation of
between .+-.0.005 to .+-.1.0 milliradian (mrad) Likewise, the
spatial tracking system described herein can be configured to
provide angular elevation velocity of between about 0.001 degree
per second (deg./sec) to 3.0 deg./sec.
[0033] The azimuth yoke used in the spatial tracking systems
described herein can extend rearwards, away from the tip of the
directional apparatus and can act as a ballast to the directional
apparatus, thus generally alleviating the elevation moment vis a
vis the elevation shaft. The azimuth yoke can be operably coupled
to the slew drive, which, like the screw-drive can be powered or
motorized by a controllable and/or reversible electrical motor, a
pneumatic device, a hydraulic device, or a device comprising at
least one of the foregoing. The slew drive can also be operably
coupled to a train of serially coupled interchangeable modular gear
units, configured to modify the slew drive's unit angular velocity
by changing the total gear ratio as a response to varying
requirements in the angular rotational velocity. For example, the
gear units can be used to decrease angular rotational velocity by
sequentially increasing the ratio ratio between the driving
mechanism and the slew drive, thus enable to track low angular
velocity and/or long range objects, with high pointing accuracy. In
an embodiment, the spatial tracking systems described herein have a
pointing accuracy of angular rotation of between .+-.0.005 to
.+-.1.0 milliradian. Likewise, the spatial tracking system
described herein can be configured to provide angular azimuthal
rotational velocity of between 0.001 degree per second (deg./sec)
to 3.0 deg./sec.
[0034] The spatial tracking systems described herein can be
constructed from any material capable of carrying the loads and
torsions required from the operation of the spatial tracking
systems described herein. Possible materials can be for example,
aluminum, steel, titanium and the like.
[0035] In an embodiment, provided herein is a two axis (elevation
and azimuth) tracking system 1000 for the purpose of tracking
target types, having a wide range of perceived angular velocities,
with a higher degree of accuracy at a lower cost and complexity
than has hitherto been possible. Turning now to FIG. 1 which is a
general isometric view of the two axis tracking system 1000
constructed in accordance with a preferred embodiment of the
present invention. A pedestal 500, operably coupled to a
foundation, supports the tracking system. The pedestal is
sufficiently elevated from the ground to allow directional
apparatus 600 adequate obstacle clearance at its most depressed
angle of elevation. The directional apparatus 600 can be coupled to
the elevation hub 100 by means of a plurality of mechanical
fasteners. The directional apparatus 600 depicted in FIG. 1 can be,
for example, an illumination device, an energy concentrating
device, a pointing device, a microphone device, an imaging device,
a data collecting or transmitting device or any other device that
requires for its operation the continuous precise positioning in
azimuth and elevation.
[0036] The desired azimuth angle can be achieved by the activation
of a motorized slew drive 300 and the desired elevation angle can
be achieved by the activation of a motorized screw drive 400
connected to the elevation hub 100. The elevation hub 100 has a
horizontal rotational degree of freedom relative to the azimuth
yoke 200, which can be operably coupled to the slew drive 300. The
slew drive can have a vertical rotational degree of freedom. The
outer ring hosed in the slew drive can be operably coupled to the
azimuth yoke and the inner ring housed in the slew drive can be
coupled to the pedestal 500; the internal gear can be configured to
rotate the outer ring relative to the fixed inner ring.
[0037] The operation and control of the pitch and rotation axes of
the tracker 1000 can be performed by a processing unit. Said
processing unit can be configured to receive information from a
plurality of onboard and external sensors, and can be configured to
execute control commands to the drive motors. The sensors,
processing and controller units can be housed in a group of
temperature controlled weather proof units 700. The processing unit
can also control and operate auxiliary system units such as: pumps,
fans, deicing devices, chillers, heating elements, lamps, cameras,
loudspeakers, warning systems etc. In an embodiment, the entire
system 1000, all the mechanical fasteners and directional devices
can be such that it survives at legally required maximum wind
speeds and safety margins.
[0038] Turning now to FIG. 2, which depicts an exploded isometric
view of an embodiment of the spatial tracking system described,
showing its part breakdown. Pedestal 500 is operably coupled to a
ground foundation and may be further stiffened, and/or made rigid
by auxiliary external bracing elements such as, for example, wires,
tubes or struts. The motorized slew drive unit 300 can be mounted
to the pedestal 500 by a circumferential array of precisely
tensioned steel bolts. The azimuth yoke unit 200 can be further
coupled to the slew gear's by a further concentric array of
precisely tensioned steel bolts. The elevation hub 100 can be
mounted to the azimuth yoke 200 with a substantial horizontal
rotational degree of freedom. The desired angle of elevation can be
achieved by a motorized geared screw drive 400 which can be
operably coupled both to the elevation hub 100 and to the azimuthal
yoke 200.
[0039] Referring now to FIG. 3, which depicts an isometric view of
the elevation hub 100. The purpose of said elevation hub 100 can be
to simultaneously provide means for attaching the directional
apparatus to the tracking unit while accurately achieving the
desired elevation angle. The directional apparatus can be coupled
to faceplate 110 by means of a plurality of mechanical fasteners.
The faceplate 110 can be machined plane and drilled in a pattern
exactly matching the directional apparatus' mating holes. As shown
in FIG. 3, a cylindrical steel housing 120 with a horizontal steel
shaft 130 can be operably coupled to the face plate 110. The shaft
protrudes from the cylindrical housing and can be fitted to a pair
of spherical bearings 140 at each end. The bearings provide an
elevational rotational degree of freedom of the steel shaft and can
also compensate for manufacturing and alignment errors, thus making
the system more robust. Vertical control horn 150 can provide means
for coupling the elevation drive to the hub and augment the
pitching moment for a given force exerted by said drive. Control
horn 150 can be operably coupled to both face plate 110 and central
cylindrical housing 120. The control horn 150 can be tapered
towards its tip, where a pair of ears 160 may be installed to
facilitate the connection of the screw drive's rod-end clevis 410.
The ears 160 may be equipped with spherical bearings 170 to enhance
the accuracy of the connection and to compensate for manufacturing
and alignment errors. The sizing of the steel components comprising
the elevation hub 100 can be performed using, for example, Finite
Element Analysis based on the limit loads of the directional
apparatus, ensuring that the maximum strength of the unit can be
obtained at the minimum weight and cost.
[0040] Referring now to FIG. 4, which depicts an isometric exploded
view of the azimuth yoke unit 200. Yoke unit 200 can consist
generally of assembled flat metal plates; reducing overall costs
while eliminating internal stresses and deformations due to
welding. The horizontal base plate 210 can be machined flat and
drilled in a pattern exactly matching the hole pattern of the slew
drive's ring. It may have a central orifice for reducing overall
weight and enabling routing of cables, tubes, hoses, wires etc.
Flat vertical side plates 220 can be coupled to the base plate 210
by means of mechanical fasteners. Said fasteners and connection
layout can be sized to sustain the maximum legal loads, including
the required safety margins, of the tracking unit. The forward
upper part of side plates 220 can be machined precisely to house
the spherical bearings 140 of the shaft 130. Side plates 220 extend
horizontally aft and can serve the plural purposes of: (i)
providing means for attachment for the screw-drive's trunnion mount
230; (ii) acting as counter weights to the installed directional
apparatus; and (iii) providing a convenient mounting surface for
the control boxes 700 housing the onboard electronics and
electrical equipment. The screw drive's trunnion mount 230 can be
coupled to the aft upper part of the side plates 220. A short shaft
can protrude from each lateral side of trunnion mount 230 and can
be fitted with spherical bearing 250. The bearing 250 can be caged
in a housing 240, which can be coupled to the side plates 220 by
tensioned mechanical fasteners.
[0041] Referring now to FIG. 5, which depicts an isometric exploded
view of the motorized slew drive unit 300 and its associated
modular gear train. The principal slew drive may consist of
typically three units: (i) inner ring 310 which can be operably
coupled to the pedestal 500 (not shown); (ii) an outer ring with
top housing 320 which can be operably coupled to the azimuth yoke
200 and worm gear unit 330 which can be configured to drive outer
ring 320 to its desired azimuthal position with high accuracy. The
size of the slew drive can be determined by, for example, the
maximum operational loads that the system can be required to
sustain. This in turn may be a function of the directional
apparatus used, choice of materials used for fabrication,
operational tolerances at the installation location and other
factors. The total gear ratio of the slew drive unit can be the
product of worm gear's 330, second stage modular gear 350 and third
stage modular gear 360. An optional variable friction unit 340, for
example: a clutch unit or a torque limiter, may be incorporated
behind the worm gear 330 should there be a requirement that at
large wind loads the directional apparatus will "wind vane" into a
trimmed protective position having minimal azimuthal torque. In
order to avoid system loads due to starting, stopping and angular
accelerations, the angular velocity of the slew drive can be
closely matched to the desired target's angular velocity. This can
be achieved by, for example, determining the desired total gear
ratio of the gear train. Since the second and third stage gear
units are modular and can be quickly exchangeable, the slew gear
unit's angular velocity can be rapidly adapted to different
targets' angular velocity. The desired azimuthal angular velocities
may range from fast moving low flying aircrafts to virtually static
astronomical targets. A reversible and/or speed controllable
electrical motor 370 can drive the slew gear unit to the desired
position. Electrical motor 370 may be controlled by a processing
unit commanding a variable speed unit for fine tuning the tracking
of the intended target to a high degree of accuracy. Electrical
motor 370 may be either: (i) single phase alternating current; (ii)
three phase alternating current; or (iii) a direct current
motor.
[0042] Turning now to FIG. 6, which depicts an isometric exploded
view of the motorized screw drive unit 400 and its associated
modular gear train. The exact positioning of the drive screw can be
configured to achieve the hub's desired elevation angle. The screw
jack worm gear housing 430 can be operably coupled to the trunnion
mount 230. The screw gear 420 can extend or retract according to
the commands issued by the processing unit. The length of the screw
gear 420 can be calculated from the limit depression and elevation
angles below and above the horizon. The diameter of the screw gear
420 can be determined by the maximum axial loads. Dimensioning a
screw gear 420 for compression loads can result in an oversize
screw due to Euler buckling effects, which are not present when the
screw is loaded in tension. In an embodiment, the tracking systems
disclosed herein ensure that the jack screw can be solely loaded in
tension, assuring that the screw diameter can be optimally matched
to the generated loads--thus ensuring minimum costs and weight
without expensive over-dimensioning. These goals can be obtained
by, for example, ensuring that screw drive rod end clevis 410 can
be coupled to the hub above the horizontal axis of rotation. In
order to avoid system loads due to starting, stopping and angular
accelerations, the angular velocity of the elevation hub can be
closely matched to the desired target's angular velocity. This can
be achieved by determining the desired total gear ratio of the
screw drive's gear train. Secondary 440 and optionally tertiary 450
modular gear units can be coupled in series to worm gear 430. Since
the second and third stage gear units are modular and can be
quickly exchangeable, the screw drive unit's linear velocity can be
quickly adapted to different targets' angular velocity. The gear
train can be driven by a reversible electrical motor 460, said
electrical motor may be controlled by a processing unit commanding
a variable speed unit for fine tuning the tracking of the intended
target to a high degree of accuracy. The electrical motor may be
either: (i) single phase alternating current; (ii) three phase
alternating current; or (iii) a direct current motor.
[0043] Turning now to FIG. 7, depicting a scheme for controlling
the tracker and its subsystem. The tracking system's processing
unit can be configured to continuously receive inputs from a
plurality of both onboard and external sensors, which communicate
with the processor either by cable, internet or wireless
communication or a combination thereof. The onboard processing
units can compile all the data received in accordance with its
internal algorithms and executes the associated commands and
instructions to the client systems, either onboard or remote
systems. An example of control scheme, is provided herewith,
whereas variations of said scheme may be implemented at any time in
accordance with varying system requirements by modifying or
replacing the sensor layout and/or the processor's control
algorithms.
[0044] The elevation and azimuth encoder readings provide the
position of the elevation and azimuth angles. The encoder readings,
combined with tracking error sensor readings, enable the processor
to issue control commands to the drive motors of both the azimuth
and elevation drives to the desired position. Auxiliary sensor
readings, such as, for example, pressures, temperatures,
vibrations, strains, velocity, mass flow etc. can be used by the
processor to control the auxiliary equipment that may be used by
the tracking system, such as: pumps, fans, chillers, deicing,
heating elements, lights, cameras, warning systems etc. Ambient
conditions sensor input can be typically obtained from a weather
station serving a plurality of trackers. The data from the weather
station may be communicated to the processor either by cable,
internet or wireless means. Typically, ambient weather data input
is used to determine whether the system's operating limits are
exceeded and if a protective stow command has to be executed.
[0045] Turning now to FIG. 8, showing a network scheme for
controlling a plurality of tracker clusters. The two axis tracker
described herein may operate either individually or as a part of a
cluster. Furthermore, globally dispersed clusters may interact with
each other to obtain the desired result. The following discussion
relates to an example of a tracker networking with n clusters of
tracking units. In a local cluster of trackers each onboard
processing unit can report to a local processing unit. The
communication between the trackers and the local processing unit
may be either by cable or wireless or a combination thereof, which
can continuously receive and transmit data as required. Said local
processing units can communicate with a remote central processing
unit, which may continuously receive data and transmit commands and
data to the local processing units. The control and supervision of
the central processing unit may be either local or remote by a
control and command station, which may be manned or autonomous. The
connection with the central processing unit may be by cable,
wireless or internet or a combination thereof. The tracker cluster
may, for example, be located in the Chilean Andes, the Central
Processing Unit in California and the Control and Command Station
in Tel-Aviv, all communicating by satellite and/or internet.
[0046] All ranges disclosed herein are inclusive of the endpoints,
and the endpoints are independently combinable with each other.
Furthermore, the terms "first," "second," "secondary", "tertiary"
and the like, herein do not denote any order, quantity, or
importance, but rather are used to denote one element from another.
The terms "a", "an" and "the" herein do not denote a limitation of
quantity, and are to be construed to cover both the singular and
the plural, unless otherwise indicated herein or clearly
contradicted by context. The suffix "(s)" as used herein is
intended to include both the singular and the plural of the term
that it modifies, thereby including one or more of that term (e.g.,
the film(s) includes one or more films). Reference throughout the
specification to "one embodiment", "another embodiment", "an
embodiment", and so forth, means that a particular element (e.g.,
feature, structure, and/or characteristic) described in connection
with the embodiment is included in at least one embodiment
described herein, and may or may not be present in other
embodiments. In addition, it is to be understood that the described
elements may be combined in any suitable manner in the various
embodiments.
[0047] The term "coupled", including its various forms such as
"operably coupling", "coupling" or "couplable", refers to and
comprises any direct or indirect, structural coupling, connection
or attachment, or adaptation or capability for such a direct or
indirect structural or operational coupling, connection or
attachment, including integrally formed components and components
which are coupled via or through another component or by the
forming process. Indirect coupling may involve coupling through an
intermediary member or adhesive, or abutting and otherwise resting
against, whether frictionally or by separate means without any
physical connection.
[0048] The term "about", when used in the description of the
technology and/or claims means that amounts, sizes, formulations,
parameters, and other quantities and characteristics are not and
need not be exact, but may be approximate and/or larger or smaller,
as desired, reflecting tolerances, conversion factors, rounding
off, measurement error and the like, and other factors known to
those of skill in the art. In general, an amount, size,
formulation, parameter or other quantity or characteristic is
"about" or "approximate" whether or not expressly stated to be such
and may include the end points of any range provided including, for
example .+-.25%, or .+-.20%, specifically, .+-.15%,or .+-.10%, more
specifically, .+-.5% of the indicated value of the disclosed
amounts, sizes, formulations, parameters, and other quantities and
characteristics.
[0049] While particular embodiments have been described,
alternatives, modifications, variations, improvements, and
substantial equivalents that are or may be presently unforeseen may
arise to applicants or others skilled in the art. Accordingly, the
appended claims as filed and as they may be amended, are intended
to embrace all such alternatives, modifications variations,
improvements, and substantial equivalents.
* * * * *